Sense of "gratification of another's desire or humor" is attested from late 14c. That of "yielding to one's inclinations" (technically self-indulgence) is from 1640s. In British history, Indulgence also refers to grants of certain liberties to Nonconformists under Charles II and James II, as special favors rather than legal rights; specifically the Declarations of Indulgence of 1672, 1687, and 1688 in England and 1669, 1672, and 1687 in Scotland.